The present invention relates to a medical safety needle assembly for a hypodermic syringe, catheter, or the like.
Disposable hypodermic syringes, needles for intravenous tubes, and catheters are often used for administering medication and performing medical procedures such as taking blood samples from patients. Safety is a prime concern in light of the spread of body fluid transmitted diseases like AIDS, hepatitis and venereal diseases, which have greatly increased both the price and the risk of health hazards resulting from accidental punctures or "sticks" with contaminated needles. The risk is shared by doctors and hospital personnel alike. Presently, safe disposal of used syringes is a serious problem due to the possibility of accidental needle sticks and due to use of used syringes by addicts for administering illicit drugs.
Presently diabetic patients administer their medication at home. After using an insulin syringe, they recap the syringes. However, prior art caps can be easily dislocated, thus exposing the needles. While it is difficult to implement safety features on insulin syringes, the present invention has overcome this problem. As the population ages, there will be a need for increased health care. However, due to economic considerations, there may be increased pressure for treatment to be provided as out-patient. The increased use of this alternative treatment plan will require development of devices suitable for non-institutional care. Pre-sterilized disposable home-use treatment kits create a need for a safety feature to be incorporated in the design of the syringe to reduce the hazards associated with disposing of used needle devices.
In order to solve the foregoing problems, heretofore modified caps or safety sheaths have been provided that can be slid over the needle, hence eliminating the risky action of recapping the needle. Examples of prior art sheath assemblies are disclosed in U.S. Pat. Nos. 4,425,120; 4,702,738; 4,801,295; 4,915,701 and 4,917,673, the disclosures of which are incorporated herein by reference thereto.
One of the problems which lingers in prior art needle sheathing assemblies is that the assemblies are too complicated and expensive and do not permit removal and disposal of the protected needle from the medical device such as a syringe. In many prior art assemblies, specially designed syringe barrels are required to interact with the sheaths, thereby requiring additional expense in manufacture. Modification to the needle by having the locking mechanism component molded on the needle may cause potential problems. During insert molding, the needles have to be inserted into the mold. This gives rise to potential catastrophic damage to the mold if the needle is not inserted properly, or if the needle falls away from its position during the closing cycle of the mold and gets trapped between the injection mold sections. Some prior art assemblies involve modifying the barrel of the syringe to incorporate the locking mechanism. In these assemblies and the sheath includes protrusions that can attach to the locking mechanism of the barrel. It is difficult to adapt this design to other medical devices because of the bulk created by the required length of the barrel safety mechanism. Some prior assemblies have the locking mechanism exposed, allowing deactivation of the locking mechanism. Further, none of the prior assemblies have the ability to indicate whether the syringe has been tampered with or used.
The present invention is designed to solve or substantially reduce the above-described problems. An added feature of this invention is the ability to incorporate this design into existing syringes already on the market and as an add-on device to present off-the-shelf hypodermic syringes.